Synthesis and Characterization of the Graft Copolymers of Starch for the Application in Packaging Films

In this study, starch was grafted with oleic acid in the presence of the initiators such as potassium persulphate and ammonium persulphate. The mixture of water/dimethyl sulphoxide (DMSO) (1:3) was used as solvent for the reaction. Grafted starch was characterized by FT-IR, X-RD, SEM and TG/DTA. Analysis of the crystallinity of the samples was done by using the X-ray diffraction technique. The reduced area under the crystalline peaks of the grafted starch showed a reduction in the crystallinity of starch after grafting as compared to native starch. SEM images of native starch and grafted starch showed that grafted starch had a rougher surface than native starch. Thermal analysis of the starch and grafted starch was studied as thermogravimetric analysis (TGA), derivative thermogravimetric analysis (DTG) and differential thermal analysis (DTA). Grafted starch was more thermally stable as compared to the native starch. It was observed that graft copolymerization of starch with oleic acid led to decrease in the crystallinity of starch and increase in the roughness on the surface of starch which may improve the compatibility of grafted starch with other biopolymers. These grafted copolymers of starch can be used with other biopolymers for the application in packaging films.